Patent GB-732795-A (GB)
Title: Improvements in or relating to material-handling machines
IPC: E02F3/348
Filed: 1952-07-21
Abstract: 732,795. Endless belt conveyers; scoop arm loaders. EIMCO CORPORATION. July 21, 1952 [Aug. 9, 1951], No. 18355/52. Classes 78(1) and 78 (3). In an overhead scoop arm loader the bucket is given a low speed high torque digging movement followed by a high speed low torque dumping movement by a drive mechanism comprising a  cam on the scoop arm operatively connected with flexible draft means. As shown in Fig. 1, the shovel 28 is pivoted about an axis 24 by a pair of chains 36 each anchored at one end 38 to a cam 32, movable with the shovel, and at the other to a winch drum 40. In operation the chains are wound spirally on the drum 40, and this, together with the shape of cams 32 provides the required torque/speed drive. The conveyer 16 is vertically adjustable and according to a modification, Fig. 5 (not shown), it may be shaped to have a discharge portion which is parallel to the ground and is lower than the highest point reached by the shovel. In another modification, Fig. 7 (not shown); both the conveyer and the complete shovel assembly are mounted on the carrier vehicle for horizontal swinging movement about vertical axes. Fig. 3 shews an arrangement of the shovel in which the chains 76, secured to cams 72 at 78, are actuated by a pair of hydraulic thrustors 82; pairs of pulleys 88 being provided to reduce lateral thrust on the thrustors. In a modification of this arrangement, Fig. 4 (not shown), the pulleys 88 are dispensed with and the thrustors are trunnion mounted on the vehicle frame. As shown in Fig. 6 pairs of rotary cams 354, 354<SP>1</SP> joined by endless chains 358, are secured to the shovel and drive-shaft 356 respectively and provide the required torque/speed drive. In a modification of this arrangement (not shown) the cam 354<SP>1</SP> is replaced by a sprocket wheel. The hydraulic thrustors or the hydraulic motors driving the winches or cams in the various arrangements described above for actuating the shovel, are represented by the thrustors 256 in Fig. 8, in which a prime mover 200 drives variable delivery pumps 202, 204 of the pressure responsive type wherein at high pressure the volume delivered by the pumps is a minimum and at low pressure the volume rises to a maximum. The pump 202 operates a traction motor 226 through a control valve 242 having forward, reverse and neutral settings A, B, C ; whilst the pump 204 feeds the thrustors 256 through a control valve 270 having up, down and neutral settings D, E, F. The circuit includes a reservoir 218 having filters 214, 216, 234 for the input and outlet conduits, and a pressure relief valve 246 to short-circuit the filters 234. In a modification, Figs. 9, 10 (not shown), the control valve 270 is modified to provide a high and low lifting torque on the shovel, and a further spring-loaded valve which is operated by the shovel in its discharging position, is provided to momentarily reverse the direction of movement of the shovel so causing it to oscillate and discharge adherent material. In another modification, Fig. 11 (not shown), oscillation of the shovel is effected by a spring-loaded valve which is operated by the shovel in its discharging position whereupon it momentarily cuts off the supply of fluid to the thrustors and vents both ends of the thrustors cylinders to the reservoir to allow the shovel to move slightly downwards under gravity. In Fig. 12 (not shown), the arrangement of Fig. 11 is modified by providing a control valve 270 with a setting in which the shovel is allowed to float downwards into its lowest position under gravity with the thrustors vented to the reservoir.